1. Field of the Invention
The present invention is related to devices for supplying web material in production processes, and more particularly to unwinding web material from a roll.
2. Description of Related Art
Generally, manufacturers and distributors can realize economic benefits by increasing the rate at which products are packaged prior to sale or further distribution. Webs or sheets of polymeric or paper materials are often used in the packaging process, such as for filler within a container, or as external protective wrapping for the product or container. During such processes, the web or sheet material is dispensed from a roll for construction into the filler material or application to the outside of the product or container. Therefore, increases in the throughput of such packaging processes generally requires either an increase of the rate at which the web or sheet material is dispensed or a reduction in downtime when exchanging rolls of web material. One way of reducing downtime is to use very large rolls of web material, sometimes referred to as xe2x80x9cjumbo rollsxe2x80x9d by those of skill in the art.
In one example of the packaging processes described above, U.S. Pat. No. 6,003,288 to Sperry et al. (xe2x80x9cSperryxe2x80x9d) discloses a packaging device that forms cushions of the type that include a plastic bag filled with a solid foam. FIG. 1 of Sperry shows the packaging device 20 mounted on a frame having lower portions 22 and upper portions 23. The device includes a first rotatable shaft 24 and a second rotatable shaft 26 for advancing a folded sheet of plastic film onto an injecting device 32 for filling with foam material. The plastic film is supplied from a stock supply roll 61 which is mounted in a pair of receiving chutes 71, as shown in FIG. 9 of Sperry. The roll of plastic film is supported by a reel shaft 60 having a core plug 56 at each end. The core plug has a spring-biased, telescoping support portion 66 that is biased to protrude out beyond the end of the roll. A plunger 80 is used to urge the support portion inwards, against the bias of the spring, to release the roll from the chute after the supply of film has been depleted. The packaging device disclosed in Sperry has the advantage of promoting easy handling of the plastic film rolls via the receiving chute and the telescoping core plug which minimizes exchange time and also allows for larger rolls that reduce exchange frequency. Despite such advantages, additional improvements in web material roll unwinding that increase efficiency of the packaging process are desirable. In addition, the telescoping support portion supports the stock supply roll, but does not positively drive the supply roll, which would lead to an additional increase in packaging production speed.
Therefore, it would be desirable to have a device and method for efficiently unwinding rolls of web material in packaging and other processes requiring supply of web material at high rates. It would be further desirable if large rolls of material were useable with the device and method in order to minimize the frequency of downtime. In addition, it would also be advantageous to combine low-frequency downtime with ease of exchanging depleted web material rolls with new web material rolls. It would be further advantageous to have a positively driven supply roll for supplying web material at high rates.
The present invention addresses the above needs and achieves other advantages by providing a device for positively driving a web material roll supported on a reel shaft having a pair of ends. The rotating device includes a female drive member coupled to one end of the reel shaft and defining an opening having a non-circular perimeter, such as a square or triangular opening. Also included is a male drive device having a rotatably powered drive shaft having an end that is congruent to the non-circular perimeter of the opening in the female drive member. The non-circular perimeter allows the reel shaft, and web material roll, to be positively rotated during unwinding. A telescoping assembly of the male drive device is capable of extending the drive shaft into the opening so as to allow co-rotation of the shaft and female member. An optional roll supporting cart may be employed to rotatably support the web material roll when aligning the male and female drive members.
In one embodiment, the present invention includes a device for rotating a web material roll supported on a reel shaft having a pair of ends. Included in the rotating device are a support frame and a female, and male, drive members. The support frame is configured to rotatably support the reel shaft and the web material roll supported on the reel shaft. Coupled to one end of the reel shaft is a female drive member that defines a receptacle which has a non-circular perimeter. The male drive device includes a motor configured to rotate a drive shaft wherein the drive shaft has at least an end with a non-circular perimeter. The non-circular perimeter of the drive shaft is congruent to the non-circular perimeter of the receptacle defined in the female drive member and is engaged therein. Further included in the male drive device is a telescoping mechanism that is capable of slidably engaging and retracting the drive end of the shaft from the receptacle. When engaged in the receptacle, the shaft is capable of rotating the reel shaft and dispensing the web material from the web material roll.
The non-circular perimeter coupling preferably has a square shape with four corners and flat surfaces so as to promote co-rotation of the drive shaft and the female member. Preferably, the drive shaft has a pulley at an end opposite the female member that is connected to a motor, such as via a belt, for rotating the drive shaft.
Optionally, the telescoping mechanism may include a second drive shaft rotatably driven by the motor and defining an axially extending opening at one end. An end of the first drive shaft opposite the drive end is slidably engaged within the opening of the second drive shaft. Extending axially along the second drive shaft is a slot within which a protuberance, such as a peg or transfixing pin, of the first drive shaft extends. The edges of the drive shaft defining the slot limit the sliding motion of the first drive shaft within the second drive shaft. A linkage may be coupled to the first drive shaft and operable to advance and retract the first drive shaft within the axially extending opening of the second drive shaft.
Mounted on one end of the second drive shaft, opposite the end defining the opening holding the first drive shaft, may be a pulley connected by a drive belt to the motor. In this arrangement, the second drive shaft is rotatably supported by a pair of aligned bearings.
The female drive member is preferably a plug fitted into an open end of the reel shaft. In another aspect, the plug includes a key that extends into a slot defined in a wall of the reel shaft so as to secure the plug against rotation within the shaft. In another option, the plug may be recessed within the open end of the reel shaft. In such a case, the drive shaft includes a base portion fitted to extend between inner wall surfaces of the reel shaft. The recessed plug and base portion allow the reel shaft to be suspended from the drive device in a cantilever arrangement.
The present invention has many advantages, including provision of a drive coupling between shaft and opening each having a non-circular perimeter that promotes co-rotation of the drive shaft assembly and reel shaft. Overall, positively driving the unwinding process allows the use of heavy jumbo rolls which minimizes frequency of downtime during roll exchange. The use of a telescoping shaft assembly on the male drive device allows the female drive plug to have a relatively simple, and cost-effective construction, unlike some prior art telescoping core plugs. The engagement linkage advantageously can be locked into a position wherein the first shaft is engaged within the opening of the female member.